#include "glCanvas.h"

// Included files for OpenGL Rendering
#ifdef __APPLE__
#include <OpenGL/gl.h>
#include <OpenGL/glu.h>
#include <GLUT/glut.h>
#include <OpenGL/glext.h>
#else
#include <GL/gl.h>
#include <GL/glu.h>
#include <GL/glut.h>
#include <GL/glext.h>
#endif

#include "glCanvas.h"
#include "argparser.h"
#include "boundingbox.h"
#include "camera.h"
#include "cloth.h"
#include "fluid.h"
#include "matrix.h"
#include "radiosity.h"
#include "raytracer.h"
#include "photon_mapping.h"
#include "mesh.h"
#include "raytree.h"
#include "utils.h"
#include<vector>

using namespace std;
// ========================================================
// static variables of GLCanvas class

Mesh* GLCanvas::mesh;
Radiosity* GLCanvas::radiosity;
RayTracer* GLCanvas::raytracer;
PhotonMapping* GLCanvas::photon_mapping;

// State of the mouse cursor
int GLCanvas::mouseButton;
int GLCanvas::mouseX;
int GLCanvas::mouseY;
int GLCanvas::display_list_index;
ArgParser* GLCanvas::args;
Camera* GLCanvas::camera;
Cloth* GLCanvas::cloth;
Fluid* GLCanvas::fluid;
bool GLCanvas::controlPressed;

void GLCanvas::Load() {
  delete cloth; 
  cloth = NULL;
  delete fluid; 
// params for the raytracing animation
 //int GLCanvas::raytracing_x;
 //int GLCanvas::raytracing_y;
 //int GLCanvas::raytracing_skip;
  fluid = NULL;
  if (args->cloth_file != "")
    cloth = new Cloth(args);
  if (args->fluid_file != "")
    fluid = new Fluid(args);
}

// ========================================================
// Initialize all appropriate OpenGL variables, set
// callback functions, and start the main event loop.
// This function will not return but can be terminated
// by calling 'exit(0)'
// ========================================================

void GLCanvas::initialize(ArgParser *_args, Mesh *_mesh, 
			  RayTracer *_raytracer, Radiosity *_radiosity, PhotonMapping *_photon_mapping) {

  args = _args;
  cloth = NULL;
  fluid = NULL;
  Load();
  Vec3f camera_position = Vec3f(0,0,4);
  Vec3f point_of_interest = Vec3f(0,0,0);
  mesh = _mesh;
  raytracer = _raytracer;
  radiosity = _radiosity;
  photon_mapping = _photon_mapping;

  // position the camera scale it so it fits in the window
  //Vec3f point_of_interest = mesh->getBoundingBox()->getCenter();
  double max_dim = mesh->getBoundingBox()->maxDim();
  //Vec3f camera_position = point_of_interest + Vec3f(0,0,4*max_dim);
  Vec3f up = Vec3f(0,1,0);
  camera = new PerspectiveCamera(camera_position, point_of_interest, up, 20 * M_PI/180.0);

  // setup glut stuff
  glutInitWindowSize(args->width, args->height);
  glutInitWindowPosition(100,100);
  glutInitDisplayMode(GLUT_DOUBLE | GLUT_DEPTH | GLUT_RGB);
  glutCreateWindow("OpenGL Viewer");

  // basic rendering 
  glEnable(GL_LIGHTING);
  glEnable(GL_DEPTH_TEST);
  glEnable(GL_NORMALIZE);
  glShadeModel(GL_SMOOTH);
  glLightModeli(GL_LIGHT_MODEL_LOCAL_VIEWER, GL_TRUE);
  GLfloat ambient[] = { 0.2, 0.2, 0.2, 1.0 };
  glLightModelfv(GL_LIGHT_MODEL_AMBIENT, ambient); 
  glLightModeli(GL_LIGHT_MODEL_LOCAL_VIEWER, GL_TRUE);
  glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, GL_FALSE);
  glCullFace(GL_BACK);
  glEnable(GL_CULL_FACE);

  display_list_index = glGenLists(1);

  // Initialize callback functions
  glutMouseFunc(mouse);
  glutMotionFunc(motion);
  glutDisplayFunc(display);
  glutReshapeFunc(reshape);
  glutKeyboardFunc(keyboard);
  glutIdleFunc(idle);

  Render();

  // Enter the main rendering loop
  glutMainLoop();
}

// ========================================================

void GLCanvas::InitLight() {
  // Set the last component of the position to 0 to indicate
  // a directional light source

  GLfloat position[4] = { 30,30,100, 1};
  GLfloat diffuse[4] = { 0.75,0.75,0.75,1};
  GLfloat specular[4] = { 0,0,0,1};
  GLfloat ambient[4] = { 0.2, 0.2, 0.2, 1.0 };

  GLfloat zero[4] = {0,0,0,0};
  glLightfv(GL_LIGHT1, GL_POSITION, position);
  glLightfv(GL_LIGHT1, GL_DIFFUSE, diffuse);
  glLightfv(GL_LIGHT1, GL_SPECULAR, specular);
  glLightfv(GL_LIGHT1, GL_AMBIENT, zero);
  glEnable(GL_LIGHT1);
  glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, GL_TRUE);
  glEnable(GL_COLOR_MATERIAL);
  glLightModelfv(GL_LIGHT_MODEL_AMBIENT, ambient);

  GLfloat spec_mat[4] = {1,1,1,1};
  float glexponent = 30;
  glMaterialfv(GL_FRONT_AND_BACK, GL_SHININESS, &glexponent);
  glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, spec_mat);

  glColorMaterial(GL_FRONT, GL_AMBIENT_AND_DIFFUSE);
  float back_color[] = { 0.5,0.5,1.0,1};
  glMaterialfv(GL_BACK, GL_AMBIENT_AND_DIFFUSE, back_color);
  glEnable(GL_LIGHT1);
}



void GLCanvas::display(void) {
  glDrawBuffer(GL_BACK);

  Vec3f bg = args->background_color;
  // Clear the display buffer, set it to the background color
  glClearColor(1,1,1,0);
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

  // Set the camera parameters
  camera->glInit(args->width, args->height);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
  InitLight(); // light will be a headlamp!
  camera->glPlaceCamera();

  if (args->intersect_backfacing)
    glDisable(GL_CULL_FACE);
  else
    glEnable(GL_CULL_FACE);

  glEnable(GL_LIGHTING);
  glEnable(GL_DEPTH_TEST);
  
  glCallList(display_list_index);
  HandleGLError(); 
   
  // Swap the back buffer with the front buffer to display
  // the scene
  glutSwapBuffers();
}

// ========================================================
// Callback function for window resize
// ========================================================

void GLCanvas::reshape(int w, int h) {
  // Set the OpenGL viewport to fill the entire window
  glViewport(0, 0, (GLsizei)w, (GLsizei)h);

  // Set the camera parameters to reflect the changes
  camera->glInit(w, h);

  args->width = w;
  args->height = h;
}

// ========================================================
// Callback function for mouse click or release
// ========================================================

void GLCanvas::mouse(int button, int state, int x, int y) {
  args->raytracing_animation = false;
  // Save the current state of the mouse.  This will be
  // used by the 'motion' function
  mouseButton = button;
  mouseX = x;
  mouseY = y;
  controlPressed = glutGetModifiers() & GLUT_ACTIVE_CTRL;
}

// ========================================================
// Callback function for mouse drag
// ========================================================

void GLCanvas::motion(int x, int y) {
  // Left button = rotation
  // (rotate camera around the up and horizontal vectors)
  if (mouseButton == GLUT_LEFT_BUTTON) {
    camera->rotateCamera(0.005*(mouseX-x), 0.005*(mouseY-y));
    mouseX = x;
    mouseY = y;
  }
  // Middle button = translation
  // (move camera perpendicular to the direction vector)
  else if (mouseButton == GLUT_MIDDLE_BUTTON) {
    camera->truckCamera((mouseX-x)*0.5, (y-mouseY)*0.5);
    mouseX = x;
    mouseY = y;
  }
  // Right button = dolly or zoom
  // (move camera along the direction vector)
  else if (mouseButton == GLUT_RIGHT_BUTTON) {
    if (controlPressed) {
      camera->zoomCamera(mouseY-y);
    } else {
      camera->dollyCamera(mouseY-y);
    }
    mouseX = x;
    mouseY = y;
  }

  // Redraw the scene with the new camera parameters
  glutPostRedisplay();
}

// ========================================================
// Callback function for keyboard events
// ========================================================

void GLCanvas::keyboard(unsigned char key, int x, int y) 
{
  switch (key) {
  case 'a': case 'A':
    // toggle continuous animation
    args->animate = !args->animate;
    if (args->animate) 
      printf ("animation started, press 'A' to stop\n");
    else
      printf ("animation stopped, press 'A' to start\n");
    // RAYTRACING STUFF
  case 'r':  case 'R':
    // animate raytracing of the scene
    args->gather_indirect=false;
    args->raytracing_animation = !args->raytracing_animation;
    /*if (args->raytracing_animation) {
      raytracing_skip = std::max(args->width,args->height) / 10;
      if (raytracing_skip % 2 == 0) raytracing_skip++;
      assert (raytracing_skip >= 1);
      raytracing_x = raytracing_skip/2;
      raytracing_y = raytracing_skip/2;
      display(); // clear out any old rendering
      printf ("raytracing animation started, press 'R' to stop\n");
    } else
      printf ("raytracing animation stopped, press 'R' to start\n"); */
    break;
  case ' ':
    // a single step of animation
    if (cloth) cloth->Animate();
    if (fluid) fluid->Animate();
     Render();
    break; 
  case 'm':  case 'M': 
    args->particles = !args->particles;
  case 't':  case 'T': {
    // visualize the ray tree for the pixel at the current mouse position
    int i = x;
    int j = glutGet(GLUT_WINDOW_HEIGHT)-y;
    RayTree::Activate();
    raytracing_skip = 1;
    TraceRay(i,j);
    RayTree::Deactivate();
    // redraw
    Render();
    break; 
  case 'v':  case 'V': 
    args->velocity = !args->velocity;
    break; }

  case 'l':  case 'L': { 
    // toggle photon rendering
    args->render_photons = !args->render_photons;
    Render();
    break; 
  case 'f':  case 'F': 
    args->force = !args->force;
    Render();
    break; 
  case 'e':  case 'E': 
    args->edge_velocity = (args->edge_velocity+1)%4;
    Render();
    break; 
  case 'd':  case 'D': 
    args->dense_velocity = (args->dense_velocity+1)%4;
    Render();
    break; 
  case 's':  case 'S': 
    args->surface = !args->surface;
    Render();
    break; 
  case 'w':  case 'W':
    args->wireframe = !args->wireframe;
    Render();
    break;
  case 'b':  case 'B':
    args->bounding_box = !args->bounding_box;
    Render();
    break;
  case 'c':  case 'C': 
    args->cubes = !args->cubes;
    Render();
    break; 
  case 'p':  case 'P': 
    args->pressure = !args->pressure;
    Render();
    break; 
  //case 'r':  case 'R': 
    // reset system
    //Load();
    //Render();
    //break; 
  case '+': case '=':
    args->isosurface += 0.1;
    if (args->isosurface >= 0.999) args->isosurface = 0.99;
    printf ("isosurface %f\n", args->isosurface);
    Render();
    break;
  case '-': case '_':
    args->isosurface -= 0.1;
    if (args->isosurface <= 0.001) args->isosurface = 0.01;
    printf ("isosurface %f\n", args->isosurface);
    Render();
    break;
  case 'q':  case 'Q':
    delete cloth;
    cloth = NULL;
    delete fluid;
    fluid = NULL;
    delete args;
    // quit
    delete GLCanvas::photon_mapping;
    delete GLCanvas::raytracer;
    delete GLCanvas::radiosity;
    delete GLCanvas::mesh;
    args = NULL;
    delete camera;
    camera = NULL;
    printf ("program exiting\n");
    exit(0);
    break;
  default:
    printf("UNKNOWN KEYBOARD INPUT  '%c'\n", key);
  }
}
}


// trace a ray through pixel (i,j) of the image an return the color
Vec3f GLCanvas::TraceRay(double i, double j) 
{
  // compute and set the pixel color
  int max_d = std::max(args->width,args->height);
  Vec3f color;
  double xpoint, ypoint;
  vector<Vec3f> colors;
  Vec3f thecolor = Vec3f(0,0,0);
  //Ray theray;
  Hit hit;
  int numsamples = args->num_antialias_samples;
  
  //std::cout << "random : " << (rand() % 200 / 100.0) - 1.0 << std::endl;
	if (numsamples > 1)
	{
		for (int h = 0; h < numsamples; ++h)
		{
			 xpoint = (i + (rand() % 100 / 100.0) - args->width/2.0)/double(max_d)+0.5; // ADD RANDOMNESS
			 ypoint = (j + (rand() % 100 / 100.0) - args->height/2.0)/double(max_d)+0.5;
			 Ray theray = camera->generateRay(Vec2f(xpoint,ypoint));
			 thecolor = raytracer->TraceRay(theray,hit); 
			 colors.push_back(thecolor);
			 RayTree::AddMainSegment(theray,0,hit.getT());
		}

		double avgx = 0;
		double avgy = 0;
		double avgz = 0;

		for (int h = 0; h < colors.size(); ++h)
		{
			 avgx += colors[h].x();
			 avgy += colors[h].y();
			 avgz += colors[h].z();
		}
		avgx = avgx / colors.size();
		avgy = avgy / colors.size();
		avgz = avgz / colors.size();

		Vec3f coloravg = Vec3f(avgx,avgy,avgz); 
		return coloravg;
	}
     

	double x = (i + 0.5 - args->width /2.0)/double(max_d)+0.5;
	double y = (j + 0.5 - args->height /2.0)/double(max_d)+0.5;
	Ray r = camera->generateRay(Vec2f(x,y));
	color = raytracer->TraceRay(r,hit);
	// add that ray for visualization
	RayTree::AddMainSegment(r,0,hit.getT());
	return color;
  }

// Scan through the image from the lower left corner across each row
// and then up to the top right.  Initially the image is sampled very
// coarsely.  Increment the static variables that track the progress
// through the scans
/*int GLCanvas::DrawPixel() {
  if (raytracing_x > args->width) {
    raytracing_x = raytracing_skip/2;
    raytracing_y += raytracing_skip;
  }
  if (raytracing_y > args->height) {
    if (raytracing_skip == 1) return 0;
    raytracing_skip = raytracing_skip / 2;
    if (raytracing_skip % 2 == 0) raytracing_skip++;
    assert (raytracing_skip >= 1);
    raytracing_x = raytracing_skip/2;
    raytracing_y = raytracing_skip/2;
    glEnd();
    glPointSize(raytracing_skip);
    glBegin(GL_POINTS);
  }

  // compute the color and position of intersection
  Vec3f color= TraceRay(raytracing_x, raytracing_y);
  double r = linear_to_srgb(color.x());
  double g = linear_to_srgb(color.y());
  double b = linear_to_srgb(color.z());
  glColor3f(r,g,b);
  double x = 2 * (raytracing_x/double(args->width)) - 1;
  double y = 2 * (raytracing_y/double(args->height)) - 1;
  glVertex3f(x,y,-1);
  raytracing_x += raytracing_skip;
  return 1;
}*/


void GLCanvas::idle() {
  if (args->animate) {
    // do 10 steps of animation before rendering
    for (int i = 0; i < 10; i++) {
      if (cloth) cloth->Animate();
      if (fluid) fluid->Animate();
    }
    Render();
  }
}



void GLCanvas::Render() {
  glNewList(display_list_index, GL_COMPILE_AND_EXECUTE);
  // =========================================================
  // put your GL drawing calls inside the display list for efficiency

  glMatrixMode(GL_MODELVIEW);

  BoundingBox box;
  if (fluid != NULL) {
    box = fluid->getBoundingBox();
    if (cloth != NULL) {
      box.Extend(cloth->getBoundingBox());
    }
  } else {
    assert (cloth != NULL);
    box = cloth->getBoundingBox(); 
  }
  
  // center the volume in the window
  Matrix m;
  m.SetToIdentity();
  Vec3f center = box.getCenter();
  m *= Matrix::MakeScale(1/float(box.maxDim()));
  m *= Matrix::MakeTranslation(-center); 
  glMultMatrixf(m.glGet());
  
  if (cloth) cloth->Paint();
  if (fluid) fluid->Paint();
  // =========================================================
  glEndList();
  glutPostRedisplay();
}

// ========================================================
// ========================================================

int HandleGLError() {
  GLenum error;
  int i = 0;
  while ((error = glGetError()) != GL_NO_ERROR) {
    printf ("GL ERROR(%d):  %s\n", i, gluErrorString(error));
    i++;
  }
  if (i == 0) return 1;
  return 0;
}
